Corrosion inhibitor



Patented AprgQ, 194G U iT m not been found sumciently corrosion. The present invention aims to provide chemicals which may be employed with such oils to reduce the corrosion of the metal.

aims to provide chemicals in hydraulic lifts, etc.

The corrosion inhibitors of the present invention are compounds of the general formula x1 aralkylI l'X wherein X and'XI are hydrogen, alkyl, or aralkyl,

that is, are nitrogenous or metal surfaces wherever the metal comes in contact with fluids causing or tending to cause corrosion of the metal surface, for example, the chemical may be incorporated in liquids used in cooling systems of internal combustion engines 20 such as monohydric or polyhydric alcohols, in lubricating oils, in textile oils, in shock absorbers,

v "STA-ms PATENT; OFFICE 2,196,261 CORROSION mnmrron Louis B. Howland, Nutley, and William P. tot

Horst, Packanack Lake, N. J., assignors, by mesne assignments, to United States Rubber Company, New York, N. Y., a corporation of New Jersey No Drawing. Application December 28, 1937, Serial No. 182,170

1 Claim. (Cl. 148-6) effective to prevent the It further as corrosion inhibitors composed essentially of di .12% soap and .12%

benzylamine.

were as follows:

compounds containing one or more aralkyl substituents directly linked to an amino nitrogen atom. are also broadly, ammonia compounds in which at least one, and preferably not more than two of the hydrogens connected to the nitrogen atom, has been replaced by an aralkyl group, the aliphatic portion of the radical being directly connected to the nitrogen atom. Compounds which are particularly effective are the monobenzylamine; dibenzylamine, and mixtures thereof. One way of preparing such compounds is by reacting an aralkyl halide, e. g. benzyl chloride, with excess aqueous sure in an autoclave, e. g. isolating, or not, the desired reaction products from the crude reaction product by distillation.

In one such method 605 pounds monia heated to about C. at a pressure of about 250 lbs. per square inch, has slowly added to it about 250 pounds of benzyl chloride. The re- 30 action temperature is about C. and is maintained about 1 hour, at the end of which time the pressure usually has dropped to approximately lbs. per square inch, after which the mix is benzylamine illustrate the effective class of corrosion inhibitors:

Example 1.Freshly pickled weighed and added to a 15%, water solution. The alcohol ammonia which may be recovered for re-use in the process. The oily layer which separates out is a crude mixture of benzylamines and may be fractionally distilled in vacuo thereby recovering a fraction boiling at 80-100 which consists largely of in well as a fraction boiling at mm. Hg. which is chiefly dibenzylamine. These two products may be blended, a being one containing abou and about 25% monobenzylamine. crude reaction mixture may be used as such for corrosion inhibiting purposes.

The following examples empl C. at 5-10 mm. Hg. onobenzylamine, as -200 C. at 5-10 desirable blend t 75% dibenzylamine However, the

oying a product benzylamine and mononess of this steel plates were by volume, alcoholsolution contained of a product consisting essentially of 25% monobenzylamine and 75% di- The solution was heated to 60 C. and air was bubbledthrough rapidly for 26 hours. The amount of corrosion was determined by visual observation and by increase in weight, the results Blank (soap Soa solution-{- hibltor These compounds Weight increase .061 gram Visual test Heavy rust.

.007 gram. No rust.

benzylamines, such as ammonia, under presat about 130 C., and

from rust.

cooled and treated with about 300 pounds of a isopropyl benzylamine, 5 50 percent caustic soda solution to liberate excess etc.

Example 2.-Pieces of steel, h stock, 3"x 4", which had been pickled, were coated with so-called "slushing oils. Another set of steel pieces were pickled and coated with slushing oil containing 1% hibitor; It was observed that coated with slushing oil graduall as, the steel plates coated with taining the inhibitor remained of aqua amtors may render certain media towards metals or alloys, it is tralize the inhibitor as by the phoric acid, oleic acid, palmitic acid or stearic acid thereby providing a salt of the inhibitor.

Examples of other aralk scope of the invention are a] such as methyl benzylamin 0t rolled tin plate of the same inthe steel pieces 40 y rusted; whereslushing oil conbright and free In some cases where the alkalinity of the inhibiunduly corrosive advisable to neuaddition of phosylamines within the kyl benzylamines e, ethyl benzylamine, beta-phenylethylamine,

1 contain (humidiflcation) tire molds, valves, bead-wire for The addition of soap greatly increases the eflectiveness oi. the inhibitors, especially when used in aqueous media. I

The addition of the inhibitors to oils that are commonly used to keep tools and machinery from rusting or to keep pickled steel from rusting on storage of in transit greatly increases the antirust properties of such oils. Other uses are for petroleum oils (refined and/or in crude oils that sulphur), air-conditioning systems tires, boilers (boiler water) fire extinguisher solutions, etc. i

The inhibitors sh uld be used in quantity sufficient to inhibit the corrosion of the metal, .1 to 5% by weight of the inhibitor being ordinarily sumcient.

Having thus described our invention, what we claim and desire to protect by Letters Patent is:

The method of inhibiting the corrosion of metals caused by contact with fluids having a corrosive influence on the metal surfaces, which comprises coating the surface of the metal with such fluids containing a dibenzylamine com- 10 pound.

LOUIS H. HOWLAND. WHLIAM P. rm HORST. 

